function Ht = range_bearing_meas_linearized_model(mu,i)
% linearized measurement model of range and bearing
% can be found P.22 of Mapping II slides
            dx = mu(3+2*(i-1)+1)-mu(1);
            dy = mu(3+2*i)-mu(2);
            rp = sqrt((dx)^2+(dy)^2);
            
            N=length(mu);
            Fi = zeros(5,N);
            Fi(1:3,1:3) = eye(3);
            Fi(4:5,3+2*(i-1)+1:3+2*i) = eye(2);
            Ht = [ -dx/rp,   -dy/rp,    0,  dx/rp,   dy/rp;
                    dy/rp^2, -dx/rp^2, -1, -dy/rp^2, dx/rp^2]*Fi;
end
